A natural mutation in the promoter of Ms-cd1 causes dominant male sterility in Brassica oleracea

Male sterility has been used for crop hybrid breeding for a long time. It has contributed greatly to crop yield increase. However, the genetic basis of male sterility has not been fully elucidated. Here, we report map-based cloning of the cabbage (Brassica oleracea) dominant male-sterile gene Ms-cd1 and reveal that it encodes a PHD-finger motif transcription factor. A natural allele Ms-cd1(P Delta-597), resulting from a 1-bp deletion in the promoter, confers dominant genic male sterility (DGMS), whereas loss-of-function ms-cd1 mutant shows recessive male sterility. We also show that the ethylene response factor BoERF1L represses the expression of Ms-cd1 by directly binding to its promoter; however, the 1-bp deletion in Ms-cd1(P Delta-597) affects the binding. Furthermore, ectopic expression of Ms-cd1(P Delta-597) confers DGMS in both dicotyledonous and monocotyledonous plant species. We thus propose that the DGMS system could be useful for breeding hybrids of multiple crop species.

Automated summary

This study cloned the dominant male-sterile gene in cabbage and found that it encodes a transcription factor. A specific mutation in the gene leads to the dominant genic male sterility (DGMS) trait. The study also discovered that an ethylene response factor can repress the expression of this gene by binding to its promoter. Additionally, ectopic expression of the mutated gene confers DGMS in multiple plant species, suggesting its potential use in hybrid breeding.